1. Field of the Invention
The present invention relates to a water-repellent film, a film formation method, a nozzle plate, an ink-jet head, and an ink-jet recording device, and in particular, the present invention relates to a water-repellent film formed by disposing water-repellent organic material on a substrate.
2. Description of the Related Art
In an ink-jet head used in an ink-jet recording device, when ink is attached onto the surface of a nozzle plate, an ink droplet ejected from a nozzle is affected, and thus, a variation occurs in an ejection direction of the ink droplet. When the variation occurs in the ejection direction of the ink droplet, it is difficult to land the ink droplet in a predetermined position on a recording medium, and thus, the variation becomes a factor of deterioration in image quality.
For this reason, a water-repellent film is formed on the surface of the nozzle plate, and thus, the ink is prevented from being attached onto the surface of the nozzle plate, and ejection performance is improved.
For example, a fluorine-containing silane coupling agent having a straight chain structure is used as the water-repellent film. The fluorine-containing silane coupling agent having a straight chain structure is able to exhibit high adhesiveness with respect to an oxide film or a surface having an OH group in spite of the thickness of a monolayer, and is able to provide high water repellency to the surface of a film formation target.
However, a problem has been known in which film deterioration due to a remarkable hydrolytic action of an aqueous solution, in particular, an alkali solution with respect to the surface on which the water-repellent film is formed and film deterioration due to a sliding operation (wiping) such as rubbing of a blade or the like occur.
In JP2008-544852A, it is disclosed that tridecafluoro-1,1,2,2-tetra-hydro-octyl trichlorosilane (FOTS) and 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane (FDTS) are used as a water-repellent silane coupling agent having a straight chain structure, and a base substrate treatment is performed, and thus, durability is enhanced.
In addition, in JP2010-76422A, it is disclosed that control of a film structure in which a monolayer is formed, and a separate film is further laminated on the monolayer is performed, and thus, durability is enhanced.